Throughout the centuries, it has been common practice for men and women to apply colored cosmetic compositions to their face, body, and hair to enhance their appearance. Make-up compositions, including eye shadow, mascara, blush, lipstick, nail polish, and hair dye typically consist of one or more pigments in a cosmetically-acceptable vehicle.
A primary goal of cosmetics is to provide a uniform application of color that creates a visually pleasing effect. Colors range from those that are intended to enhance natural skin or hair color, those used to cover up or hide an undesired existing color, and those that are purely frivolous and ornamental. These latter colors gained popularity during the “punk rock” era of the 1980's, and have recently regained popularity, due largely to their widespread use by Dennis Rodman, and other celebrities.
Photochromic compounds are compounds that change color upon exposure to light, then revert back to their original color once the light source is removed. In comparison, thermochromic compounds are compounds that change color upon exposure to different temperatures. Photochromic and thermochromic compounds (hereinafter “chromic compounds”) have been proposed for use in many types of coloring compositions, including inks, paints, and cosmetics.
For instance, U.S. Pat. Nos. 6,139,779 and 4,421,560 describe thermochromic ink formulations. It has been found, however, that the compositions of these patents tend to rapidly lose their thermochromic properties.
U.S. Pat. No. 6,123,952 describes the use of a photochromic-coloring agent in a cosmetic composition. However, the composition of this patent is thermally irreversible, such that once the photochromic properties of the composition have been activated, the composition can no longer revert back to its original color.
There is therefore a need in the art for a chromic coloring agent for use in cosmetic formulations that is reversible, and maintains its thermochromic/photochromic capabilities for a longer period of time than conventional chromic agents.
It is therefore a primary object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that is reversible, such that once the chromic properties of the composition have been activated, the composition can revert back to its original color.
It is a further object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that maintains its thermochromic/photochromic properties for a relatively longer period of time than conventional chromic agents.
It is a further object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that allows the user to create unique color changing effects and combinations.
It is yet a further object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that is easily applied and removed.
It is still a further object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that is simple and economical to manufacture.
It is a further object of the present invention to provide a thermochromic and/or photochromic cosmetic composition that is shelf stable for at least two years.
These and other objects of the present invention will become clear from the following detailed description of the invention.